Suggesting query items based on frequent item sets

ABSTRACT

A system receives a character sequence entered in a search box, identifies a first item that includes the character sequence and a second item that includes the character sequence, identifies a first item set that includes the first item and a second item set that includes the second item; and outputs the first item set and the second item set to a location associated with the search box. The system receives a selection of a third item from the first item set, identifies a third item set that includes the third item and a fourth item set that includes the third item, and outputs the third item set and the fourth item set to the location associated with the search box. The system receives a selection of any item set from the location associated with the search box, and executes a search based on the selected item set.

COPYRIGHT NOTICE

A portion of the disclosure of this patent document contains material which is subject to copyright protection. The copyright owner has no objection to the facsimile reproduction by anyone of the patent document or the patent disclosure, as it appears in the Patent and Trademark Office patent file or records, but otherwise reserves all copyright rights whatsoever.

BACKGROUND

The subject matter discussed in the background section should not be assumed to be prior art merely as a result of its mention in the background section. Similarly, a problem mentioned in the background section or associated with the subject matter of the background section should not be assumed to have been previously recognized in the prior art. The subject matter in the background section merely represents different approaches, which in and of themselves may also be inventions.

Given a large collection (millions or billions) of small sets of items (which may be called market baskets) sampled from an existing universe of items (such as products, services, or search terms), automated recommendation of items is often based on the identification of frequently occurring item sets, which are sets of items that were purchased together. There are other recommendation algorithms, such collaborative filtering, for circumstances when system users sample one item at a time. Frequent item sets is for circumstances when system users sample items together. Market basket analysis is a process in which retailers evaluate information in such market baskets to understand the purchase behavior of customers and/or the searching behavior of potential customers. This information can then be analyzed for purposes of cross-selling, the practice of selling an additional product or service to an existing customer. Examples of market basket analysis for cross selling are automated recommendations such as “customers who bought book A also bought book B,” and “People who read ‘History of Portugal’ were also interested in ‘Naval History.’” Many database systems use the Apriori algorithm to evaluate frequent item sets for market basket analysis. The Apriori algorithm first identifies the individual items that appear the most frequently in a database's item sets, and then extends these frequent individual items to larger and larger item sets, provided that the larger item sets appear sufficiently often in the database's item sets.

Depending on the nature and size of the item sets, a frequent pattern (FP) tree algorithm can execute much faster than the Apriori algorithm executes. The frequent pattern tree algorithm places item sets in a tree, recursively building the tree based on the count for each of the items in the item sets. For each item set, the frequent pattern tree algorithm sorts its items, left to right, in descending order. The frequent pattern tree algorithm identifies the leftmost item with the most item sets, removes this item from the item sets, and represents this item as a root node with the count of all its item sets. Then the frequent pattern tree algorithm recursively looks at the second position in the descending order of items, and finds the most represented remaining item, and represents that item as a child node. The frequent pattern tree algorithm repeats this process, representing more items as child nodes until the frequent pattern tree algorithm is done with the descending order of items, thereby creating a tree in which each original item set is a path in the tree. Then the frequent pattern tree algorithm generates all of the possible item sets by proceeding upward from the leaves in the tree. If the item sets include enough repetition of items, the frequent pattern tree algorithm can execute in memory.

A search box can be a graphical control element used in computer programs, such as file managers, or web browsers, and on web sites. A search box may be a single-line text box with the dedicated function of accepting user input that is used as a query to search a database. Search boxes on web pages can be used to allow users to enter a query to be submitted to a Web search engine server-side script, where an index database is searched for entries that contain one or more of the user's search terms, which may be called query items. Search boxes can be accompanied by a search button, which may be indicated by a magnifying glass symbol, to submit a query for a search. However, the search button can be omitted as the user may press the enter key to submit a query for a search, or the query can be sent automatically to present the user with real-time results. Depending on the particular implementation, a search box may be accompanied by a drop-down list to present the users with past queries or suggested queries. Search boxes can have other features to help the user, such as autocomplete, a spelling checker, etc. Search boxes may also be accompanied by drop-down menus or other input controls to allow the user to restrict the search or choose for which type of content to search. A suggested query drop-down list can show a user shortcuts while a query is entered into a search box. Before the query is completely entered, a drop-down list with the suggested completions may appear to provide options to select. The suggested queries can enable the searcher to complete the required search quickly. As a form of auto completion, the suggested query list is distinct from a search history in that the suggested query list attempts to be predictive even when the user is entering a query for the first time. Data that supports suggested queries may come from popular searches, sponsors, geographic location, or other sources. These suggested query lists can be used by operating systems, web browsers, and various websites, particularly search engines.

Autocomplete may be a feature in which an application predicts the rest of a word or a query that a user is typing. In graphical user interfaces, users can press the tab key to accept a suggested completion or the down arrow key to accept one of several suggested completions. Autocomplete speeds up human-computer interactions when it correctly predicts the word or query that a user intends to enter after only a few characters have been entered into an input field.

BRIEF DESCRIPTION OF THE DRAWINGS

In the following drawings like reference numbers are used to refer to like elements. Although the following figures depict various examples, the one or more implementations are not limited to the examples depicted in the figures.

FIG. 1 depicts an operational flow diagram illustrating a high level overview of a method for suggesting query items based on frequent item sets, in an embodiment;

FIG. 2 depicts an operational flow diagram illustrating a high level overview of another method for suggesting query items based on frequent item sets, in an embodiment;

FIGS. 3A-B illustrate block diagrams of extremely simplified examples of item sets and an array for suggesting query items based on frequent item sets, in an embodiment;

FIG. 4 illustrates a block diagram of an example of an environment wherein an on-demand database service might be used; and

FIG. 5 illustrates a block diagram of an embodiment of elements of FIG. 4 and various possible interconnections between these elements.

DETAILED DESCRIPTION General Overview

In accordance with embodiments described herein, there are provided methods and systems for suggesting query items based on frequent item sets. A system receives a character sequence entered in a search box, identifies a first item that includes the character sequence and a second item that includes the character sequence, identifies a first item set that includes the first item and a second item set that includes the second item; and outputs the first item set and the second item set to a location associated with the search box. The system receives a selection of a third item from the first item set, identifies a third item set that includes the third item and a fourth item set that includes the third item, and outputs the third item set and the fourth item set to the location associated with the search box. The system receives a selection of any item set from the location associated with the search box, and executes a search based on the selected item set.

For example, when a user enters the character sequence “co” in the user's search box, a database system identifies the item “computer” that includes the character sequence “co” and the item “contacts” that includes the character sequence “co.” Then the database system identifies the item set “computer sales California” that includes the identified item “computer” and the item set “contacts acme corporation” that includes the identified item “contacts,” and outputs the item sets “computer sales California” and “contacts acme corporation” to the search box's drop-down list. When the user selects the items “computer sales” from the item set “computer sales California,” the database system identifies the item set “computer sales Los Angeles” that includes the selected items “computer sales” and the item set “computer sales San Francisco” that includes the selected items “computer sales.” Next, the databases system outputs the item sets “computer sales Los Angeles” and “computer sales San Francisco” to the search box's drop-down list. The user selects the item set “computer sales San Francisco” from the drop-down list, and the databases system executes a search using the selected item set, “computer sales San Francisco.” In summary, the database system initially suggests the query items “computer sales California,” receives the user's selection of the items “computer sales” from the initially suggested query items, suggests additional query items that include the user-selected items “computer sales,” receives the user's selection of a suggested additional query item, and only then executes a search based on the user-selected additional query item. In contrast, the prior art would immediately execute a search based on a user selecting anything from the initially suggested query items “computer sales California,” thereby preventing the user from submitting additional query terms until after the search that used the initially suggested query terms.

Systems and methods are provided for suggesting query items based on frequent item sets. As used herein, the term multi-tenant database system refers to those systems in which various elements of hardware and software of the database system may be shared by one or more customers. For example, a given application server may simultaneously process requests for a great number of customers, and a given database table may store rows for a potentially much greater number of customers. As used herein, the term query plan refers to a set of steps used to access information in a database system. Next, methods and mechanisms for suggesting query items based on frequent item sets will be described with reference to example embodiments. The following detailed description will first describe methods for suggesting query items based on frequent item sets, and then describe an extremely simplified example of item sets and an array for suggesting query items based on frequent item sets.

While one or more implementations and techniques are described with reference to an embodiment in which suggesting query items based on frequent item sets is implemented in a system having an application server providing a front end for an on-demand database service capable of supporting multiple tenants, the one or more implementations and techniques are not limited to multi-tenant databases nor deployment on application servers. Embodiments may be practiced using other database architectures, i.e., ORACLE®, DB2® by IBM and the like without departing from the scope of the embodiments claimed.

Any of the embodiments described herein may be used alone or together with one another in any combination. The one or more implementations encompassed within this specification may also include embodiments that are only partially mentioned or alluded to or are not mentioned or alluded to at all in this brief summary or in the abstract. Although various embodiments may have been motivated by various deficiencies with the prior art, which may be discussed or alluded to in one or more places in the specification, the embodiments do not necessarily address any of these deficiencies. In other words, different embodiments may address different deficiencies that may be discussed in the specification. Some embodiments may only partially address some deficiencies or just one deficiency that may be discussed in the specification, and some embodiments may not address any of these deficiencies.

FIG. 1 depicts an operational flow diagram illustrating a high level overview of a method 100 for suggesting query items based on frequent item sets. The method 100 may be implemented on either a centralized computing platform or in parallel on a distributed computing platform, such as on Map/Reduce or Spark.

A system receives a character sequence entered in a search box, box 102. The system suggests query items based on the user-entered character sequence. For example and without limitation, this can include the database system receiving a user's entry of the character sequence “co” in the user's search box. In another example, the database system receives a user's entry of the character sequence “comp” in the user's search box. Aspects of the database system are described below in reference to FIG. 4 and FIG. 5. As indicated above, a search box can be a graphical control element used by computer programs, with the dedicated function of accepting user input that is used as a query to search a database. A character sequence can be part or all of an ordered group of symbols, such as the letters “co” and the letters “computer.” A user may use tactile input, such as a keyboard or touchpad, and/or an audio input, such as speaking to a microphone that communicates with a speech-to-text application, to enter a character sequence in a search box.

Having received a character sequence, the system identifies a first item that includes the character sequence and a second item that includes the character sequence, box 104. The system suggests query items based on items that include the character sequence. By way of example and without limitation, this can include the database system identifying the item “computer” that includes the character sequence “co” and the item “contacts” that includes the character sequence “co.” Although this example describes the database system identifying two items that include the character sequence, the database system may identify any number of items that include the character sequence. While this example describes the database system identifying items that begin with the character sequence, the database system may identify items that include but do not begin with the character sequence, such as the item “supercomputer” that includes but does not begin with the character sequence “co.” An item can be anything that the database system can associate with a database system user's set, such as a search term, a contact, an account, a lead, an opportunity, a product, a service, or any digital object.

The database system may identify the first item and the second item based on the first item and the second item being associated with corresponding item counts that are larger than corresponding item counts associated with multiple other items. For example, the database system identifies a count of 987 for the item “computer,” a count of 876 for the item “contacts,” a count of 765 for the item “company,” and a count of 654 for the item “compute,” such that the database system identifies only the two items, “computer” and “contacts,” which include the character sequence “co” and have the largest counts, for subsequent processing.

The database system can maintain a map from each character sequence, such as “co,” which may be referred to as a prefix, to each corresponding item, such as “computer,” “contacts,” “company,” and “compute.” Since users may not have searched for every item in the database, the database system can maintain a map for all character sequences that correspond to all database items, whether or not any user has searched for the database item.

The database system may use a hash schema that enables the database system to receive a character sequence and then quickly identify corresponding items and their item counts. If the database system only identifies items for which a user has searched, then the item counts indicate how frequently corresponding items have appeared in previous searches. If the database system does not identify items for which a user has searched, then the database system applies a different metric to candidate items, such as the items' frequencies in the database. If the database system identifies items for which a user has searched and items for which a user has not searched, then the item counts indicate how frequently corresponding items have appeared in previous searches and indicate how frequently corresponding items appear in the database.

The database system can consider how frequently a candidate item was chosen from searches with the current prefix, such as the number of searches that included the prefix “co” and the number of selections of the item “contact” based on the prefix “co.” The database system can also consider the number of item sets in the database that include the prefix “co”, the number of item sets in the database that include the item “contact,” or how many contacts include a specific name. These considerations of previously searched items and considerations of inclusions in the data base each provide a normalized comparable number. The database system may adjust such numbers by the likelihood that a user is inputting an item that has never been searched for previously. An item count can be a measure or a number of a thing, such as the 7 instances when a system user submitted a specific type of query that included the word “James,” or the 6 occurrences of Contact A in a collection of item sets. In another example, the database system identifies a count of 987 for the item “computer,” a count of 765 for the item “company,” a count of 654 for the item “compute,” and a count of 543 for the item “compare,” such that the database system identifies only the two items, “computer” and “company,” which include the character sequence “comp” and have the largest counts, for subsequent processing.

After identifying a first item and a second item that both include the received character sequence, the system identifies a first item set that includes the first item and a second item set that includes the second item, box 106. The system suggests query items using item sets that include the user-entered character sequence. In embodiments, this can include the database system identifying the item set “computer sales California” that includes the identified item “computer” and the item set “contacts Acme Corporation” that includes the identified item “contact.” Although this example describes the database system identifying two item sets that include any of the identified items, the database system may identify any number of item sets that include any of the identified items. While this example describes the database system identifying item sets that begin with any of the identified items, the database system may identify item sets that include but do not begin with any of the identified items, such as the item set “San Francisco computer sales” that includes but does not begin with the identified item “computer.” An item set can be any group or collection of entities that are associated with a specific user at a period in time. Examples of item sets include the 9 contacts that an organization member purchased on Monday, the 10 contacts that the organization member purchased on Tuesday, the 8 contacts that the organization member searched for on Tuesday, the 13 accounts that an organization purchased on Wednesday morning, the 12 accounts that the organization purchased on Wednesday afternoon, and the 11 accounts that the organization searched for on Wednesday night.

The database system may identify the first item set and the second item set based on the first item set and the second item set being associated with corresponding item set counts that are larger than corresponding item set counts associated with multiple other item sets. For example, the database system identifies a count of 432 for the item set “computer sales California,” a count of 321 for the item “contacts acme corporation,” a count of 210 for the item “computer repairs New York,” and a count of 109 for the item “contacts MegaCorp,” such that the database system identifies only the two item sets, “computer sales California” and “contacts acme corporation,” which include either of the identified items “computer” or “contacts” and have the largest counts, for subsequent processing. An item set count can be a measure or a number of a thing, such as the 7 instances when a system user submitted a specific type of query that included the words “James” and “Jordan,” or the 6 occurrences of Contact A and Contact B in a collection of item sets. Each identified item set may or may not be associated with a prior search. For example, the count of 432 for the item set “computer sales California” is based on 432 prior database searches that each included the items “computer,” “sales,” and “California,” whereas the count of 321 for the item “contacts acme corporation,” is based on 321 instances when system users purchased contact information for Acme Corporation employees.

The database system can maintain a map from each item, such as “computer,” to each corresponding item set, such as “computer sales California,” “and “computer repair New York.” Since users may not have used every item set in the database as the basis for a search, the database system can maintain a map for all items that correspond to all database item sets, whether or not any user has used the database item set as the basis for a search. The database system may use a hash schema that enables the database system to receive an item and then quickly identify corresponding item sets and their item set counts. Although this example describes the database system identifying one item set that is based on a prior database search and identifying one item set that is not based on a prior database search, the database system may identify any number of item sets that are based on prior database searches and identify any number of item sets that are not based on prior database searches. The method 200 described below and depicted in FIG. 2 details how the database system may identify frequent item sets that include an identified item.

Having identified a first item set and a second item set that each include a character sequence, the system outputs the first item set and the second item set to a location associated with the search box, box 108. The system suggests query items using item sets that include the user-entered character sequence. For example and without limitation, this can include the database system outputting the item sets “computer sales California” and “contacts acme corporation” to the search box's drop-down list. A location associated with a search box can be a drop-down list that is visually proximate to the search box, or a position within a sufficiently large search box itself. The database system may output items from the first item set in an item sequence associated with a prior search. For example, the database system outputs the item set “California computer sales” to the search box's drop-down list because most of the prior searches that included the items “computer,” “sales,” and “California” listed these items in an order that began with the item “California” and ended with the item “sales.”

Alternatively, the database system outputs the item set “computer sales California” because the first item “computer” includes the user-entered character sequence “co,” and because more prior searches reference the second item “sales” than prior searches that reference the third item “California.” As yet another option, the database system outputs the item set “sales computer California” because more prior searches reference the first item “sales” than prior searches that reference the second item “computer,” and more prior searches reference the second item “computer” than prior searches that reference the third item “California.”

In an example in which the items' output order is not based on prior searches, the database system outputs the item set “computer sales California” because the first item “computer” includes the user-entered character sequence “co,” and because the count of the second item “sales” in the database is greater than the count of the third item “California” in the database. In another example in which the items' output order is not based on prior searches, the database system outputs the item set “sales computer California” because the count of the first item “sales” is greater than the count of the second item “computer” in the database, and the count of the second item “computer” in the database is greater than the count of the third item “California” in the database. The order for outputting items may be configurable by the database system and/or the user. An item sequence can be the order in which things in a set were originally listed, such as the order listing the items “California computer sales” during prior database searches. A prior search can be a previous instance when a database system responded to a user submitting query items.

After outputting the first item set and the second item set, the system receives a selection of a third item from the first item set, box 110. The system suggests query items based on the user's selection of an item from an item set. By way of example and without limitation, this can include the database system receiving the user's selection of the item set “computer sales California.” In an alternative example, the database system receives the user's selection of the items “computer sales” from the item set “computer sales California.” A selection of an item from an item set can be made by a user positioning an indicator, a pointer, or a cursor at a location where the item is displayed on a user interface, or by the user's audio command via a microphone.

In an embodiment, the user positions a touch pad cursor over the item “sales” in the item set “computer sales California,” and presses the enter key, which selects both the indicated item “sales” and the preceding item “computer,” but does not select the following item “California.” For this example, if the user had wanted to also select the item “California,” the user could have positioned the touch pad cursor over the item “California” and pressed the enter key, which would have selected the item set “computer sales California.” Depending on the database system's configurations, the database system can either execute a search based on such a selection of an entire item set, or wait for the user to enter additional query items.

In an example based on different configurations, the user positions a touch pad cursor over the item “sales” in the item set “computer sales California,” and presses the enter key, which selects only the indicated item “sales,” but does not select the preceding item “computer” or the following item “California,” as the user has the capability to individually select each item in an item set before pressing the enter key. In an alternative example, the database system responds to the user entering the character sequence “co” by outputting the item set “computer sales California” in the form of the item subsets “computer,” “computer sales,” “computer California,” and “computer sales California,” which enables the user to select any of these item subsets by positioning the touch pad cursor over the desired item subset and pressing the enter key.

Having received a selection of the third item from the first item set, the system identifies a third item set that includes the third item and a fourth item set that includes the third item, box 112. Likelihoods are conditioned, in that the system displays item sets that are likely given a user's entry of a character sequence in a search box, then when the user has selected something from the displayed item sets, the system displays additional item sets which are highly likely, given the user's selection. The system suggests query items using item sets that include an item that the user selected from a previously output item set. In embodiments, this can include the database system identifying the item set “computer sales Los Angeles” that includes the selected items “computer sales” and the item set “computer sales San Francisco” that includes the selected items “computer sales.” In this example, the database system responds to the user selecting the items “computer sales” and the user not selecting the item “California” by identifying item sets that include the user's selected items. Although this example describes the database system identifying two item sets based on a user's selection(s), the database system may identify any number of item sets based on the user's selection(s). While this example describes the database system identifying item sets that begin with a user's selection(s), the database system may identify item sets that include but do not begin with the user's selection(s), such as the item set “San Francisco computer sales” that includes but does not begin with the user's selected items “computer sales.”

The database system may identify the third item set and the fourth item set based on the third item set and the fourth item set being associated with corresponding item set counts that are larger than corresponding item set counts associated with multiple other item sets. For example, the database system identifies a count of 432 for the item set “computer sales Los Angeles,” a count of 321 for the item “computer sales San Francisco,” a count of 210 for the item “computer sales new York,” and a count of 109 for the item “computer sales Texas,” such that the database system identifies only the two item sets, “computer sales California” and “contacts acme corporation,” which include the selected items “computer” and “sales” and have the largest counts, for subsequent processing. Each identified item set may or may not be associated with a prior search. For example, the count of 432 for the item set “computer sales Los Angeles” is based on 432 prior database searches that each included the items “computer,” “sales,” “Los,” and “Angeles,” whereas the count of 321 for the item “computer sales San Francisco,” is based on 321 instances when system users purchased contact information for computer sales representatives in San Francisco. The system translates such counts into likelihoods by dividing the counts by the total number of item sets in the database.

The database system can maintain a map from items, such as “computer sales,” to each corresponding item set, such as “computer sales Los Angeles,” “and “computer sales San Francisco.” Since users may not have used every item set in the database as the basis for a search, the database system can maintain a map for items that correspond to all database item sets, whether or not any user has used the database item set as the basis for a search. The database system may use a hash schema that enables the database system to receive items and then quickly identify corresponding item sets and their item set counts. Although this example describes the database system identifying one item set that is based on a prior database search and identifying one item set that is not based on a prior database search, the database system may identify any number of item sets that are based on prior database searches and identify any number of item sets that are not based on prior database searches. The method 200 described below and depicted in FIG. 2 details how the database system may identify frequent item sets that include identified items.

After identifying the third item set that includes the third item and the fourth item set that includes the third item, the system outputs the third item set and the fourth item set to the location associated with the search box, box 114. The system suggests query items using item sets that include user-selected items. For example and without limitation, this can include the database system outputting the item sets “computer sales Los Angeles” and “computer sales San Francisco” to the search box's drop-down list. The database system may output the items from an item set in an item sequence associated with a prior search. For example, the database system outputs the item set “San Francisco computer sales” to the search box's drop-down list because most of the prior searches that included the items “computer,” “sales,” “San,” and “Francisco” listed these items in an order that began with the items “San Francisco” and ended with the item “sales.” Alternatively, the database system outputs the item set “computer sales San Francisco” because the first item “computer” includes the user-entered character sequence “co,” and because more prior searches reference the second item “sales” than prior searches that reference the third item “San,” and more prior searches reference the third item “San” than prior searches that reference the fourth item “Francisco.” As yet another option, the database system outputs the item set “sales computer San Francisco” because more prior searches reference the first item “sales” than prior searches that reference the second item “computer,” more prior searches reference the second item “computer” than prior searches that reference the third item “San,” and more prior searches reference the third item “San” than prior searches that reference the fourth item “Francisco.”

In an example in which the items' output order is not based on prior searches, the database system outputs the item set “computer sales San Francisco” because the first item “computer” includes the user-entered character sequence “co,” and because the count of the second item “sales” in the database is greater than the count of the third item “San” in the database, and the count of the third item “San” in the database is greater than the count of the fourth item “Francisco” in the database. In another example in which the items' output order is not based on prior searches, the database system outputs the item set “sales computer San Francisco” because the count of the first item “sales” in the database is greater than the count of the second item “computer” in the database, the count of the second item “computer” is greater than the count of the third item “San” in the database, and the count of the third item “San” in the database is greater than the count of the fourth item “Francisco” in the database. The order for outputting items may be configurable by the database system and/or the user.

Having output third and fourth item sets that include a user-selected item, the system optionally receives a selection of a fourth item from the third item set, box 116. The system suggests query items based on user selections of items from item sets. By way of example and without limitation, this can include the database system receiving the user's selection of the item “San” from the item set “computer sales San Francisco.” Even though this example describes the database system enabling the user to select items from output item sets two times before executing a search based on a selected item set, the database system may enable the user to select items from output item sets any number of times before executing a search based on the selected item set. In this example, the user positions the touch pad cursor over the item “San” in the item set “computer sales San Francisco,” and presses the enter key, which selects both the indicated item “san” and the preceding items “computer sales,” but does not select the following item “Francisco.” For this example, if the user had wanted to also select the item “Francisco,” the user could have positioned the touch pad cursor over the item “Francisco” and pressed the enter key, which would have selected the item set “computer sales San Francisco.” Depending on the database system's configurations, the database system can either execute a search based on such a selection of an entire item set, or wait for the user to enter additional query items.

In an example based on different configurations, the user positions a touch pad cursor over the item “San” in the item set “computer sales San Francisco,” and presses the enter key, which selects only the indicated item “San,” but does not select the preceding items “computer sales” or the following item “Francisco,” as the user has the capability to individually select each item in an item set before pressing the enter key. In an alternative example, the database system responds to the user entering the character sequence “co” by outputting the item set “computer sales San Francisco” in the form of the item subsets “computer,” “computer sales,” “computer San,” “computer sales San,” “computer Francisco,” “computer sales Francisco,” “computer San Francisco,” and “computer sales San Francisco,” which enables the user to select any of these item subsets by positioning the touch pad cursor over the desired item subset and pressing the enter key.

After optionally receiving a selection of the fourth item from the third item set, the system optionally identifies a fifth item set that includes the fourth item and a sixth item set that includes the fourth item, box 118. The system suggests query items using item sets that include user-selected items. In embodiments, this can include the database system identifying the item set “San Francisco computer sales James Jordan” that includes the selected items “computer sales San” and the item set “San Jose computer sales Jordan James” that includes the selected items “computer sales San.” Even though this example describes the database system identifying item sets based on the user selecting items from output item sets two times before executing a search based on a selected item set, the database system may identify item sets based on the user selecting items from output item sets any number of times before executing a search based on the selected item set.

In this example, the database system responds to the user selecting the items “computer sales san” and the user not selecting the item “Francisco” by identifying item sets that include the user's selected items. Although this example describes the database system identifying two item sets based on a user's selection(s), the database system may identify any number of item sets based on the user's selection(s). While this example describes the database system identifying item sets that begin with a user's selection(s), the database system may identify item sets that include but do not begin with the user's selection(s), such as the item set “San Francisco computer sales James Jordan” that includes but does not begin with the user's selected items “computer sales San.”

The database system may identify the fifth item set and the sixth item set based on the fifth item set and the sixth item set being associated with corresponding item set counts that are larger than corresponding item set counts associated with multiple other item sets. For example, the database system identifies a count of 432 for the item set “San Francisco computer sales James Jordan,” a count of 321 for the item “San Jose computer sales Jordan James,” a count of 210 for the item “San Diego computer sales,” and a count of 109 for the item “San Francisco computer sales John Smith,” such that the database system identifies only the two item sets, “San Francisco computer sales James Jordan” and “San Jose computer sales Jordan James,” which include the selected items “computer,” “sales,” and “San,” and have the largest counts, for subsequent processing. Each identified item set may or may not be associated with a prior search. For example, the count of 432 for the item set “San Francisco computer sales James Jordan” is based on 432 prior database searches that each included the items “computer,” “sales,” “San,” “Francisco,” “James,” and “Jordan,” whereas the count of 321 for the item “San Jose computer sales Jordan James,” is based on 321 instances when system users purchased contact information for a San Jose computer sales representative named Jordan James.

The database system can maintain a map from items, such as “computer sales San,” to each corresponding item set, such as “San Francisco computer sales James Jordan,” “and “San Jose computer sales Jordan James.” Since users may not have used every item set in the database as the basis for a search, the database system can maintain a map for items that correspond to all database item sets, whether or not any user has used the database item set as the basis for a search. The database system may use a hash schema that enables the database system to receive items and then quickly identify corresponding item sets and their item set counts. Although this example describes the database system identifying one item set that is based on a prior database search and identifying one item set that is not based on a prior database search, the database system may identify any number of item sets that are based on prior database searches and identify any number of item sets that are not based on prior database searches. The method 200 described below and depicted in FIG. 2 details how the database system may identify frequent item sets that include identified items.

Having optionally identified the fifth item set that includes the user-selected fourth item and the sixth item set that includes the user-selected fourth item, the system optionally outputs the fifth item set and the sixth item set to the location associated with the search box, box 120. The system suggests query items using item sets that include user-selected items. For example and without limitation, this can include the database system outputting the item sets “San Francisco computer sales James Jordan” and “San Jose computer sales Jordan James.” Even though this example describes the database system outputting item sets two times before executing a search based on a selected item set, the database system may output item sets any number of times before executing a search based on the selected item set.

The database system may output the items from an item set in an item sequence that is associated with a prior search. For example, the database system outputs the item set “San Francisco computer sales James Jordan” to the search box's drop-down list because most of the prior searches that included the items “computer,” “sales,” “San,” “Francisco,” “James,” and “Jordan” listed these items in an order that began with the items “San Francisco” and ended with the items “James Jordan.” The listed order of the items in an item set that is output may be significant in some instances, such as when “James” is listed before “Jordan” to indicate that the San Francisco computer sales representative has a given name of James and a family name of Jordan, which enables differentiation from the San Jose computer sales representative who has a given name of Jordan and a family name of James. Alternatively, the database system outputs the item set “computer sales San Francisco James Jordan” because the first item “computer” includes the user-entered character sequence “co,” and because more prior searches reference the second item “sales” than prior searches that reference the third item “San.” The item set “computer sales San Francisco James Jordan” is output also because more prior searches reference the third item “San” than prior searches that reference the fourth item “Francisco,” more prior searches reference the fourth item “Francisco” than prior searches that reference the fifth item “James,” and more prior searches reference the fifth item “James” than prior searches that reference the sixth item “Jordan.” As yet another option, the database system outputs the item set “sales computer San Francisco James Jordan” because more prior searches reference the first item “sales” than prior searches that reference the second item “computer,” and more prior searches reference the second item “computer” than prior searches that reference the third item “San.” The item set “sales computer San Francisco James Jordan” is output also because more prior searches reference the third item “San” than prior searches that reference the fourth item “Francisco,” more prior searches reference the fourth item “Francisco” than prior searches that reference the fifth item “James,” and more prior searches reference the fifth item “James” than prior searches that reference the sixth item “Jordan.”

In an example in which the items' output order is not based on prior searches, the database system outputs the item set “computer sales San Francisco James Jordan” because the first item “computer” includes the user-entered character sequence “co,” and because the count of the second item “sales” in the database is greater than the count the third item “San” in the database, which is greater than the count of the third item “San” in the database, which is greater than the count of the fourth item “Francisco” in the database, which is greater than the count of the fifth item “James” in the database, which is greater than the count of the sixth item “Jordan” in the database. In another example in which the items' output order is not based on prior searches, the database system outputs the item set “sales computer San Francisco James Jordan” because the count of the first item “sales” in the database, which is greater than the count of the second item “computer” in the database, which is greater than the count of the third item “San” in the database, which is greater than the count of the fourth item “Francisco” in the database, which is greater than the count of the fifth item “James” in the database, which is greater than the count of the sixth item “Jordan” in the database. The order for outputting items may be configurable by the database system and/or the user.

Having output item sets that include a user-selected item, the system receives a selection of any item set from the location associated with the search box, box 122. The system suggests query items based on user selections of items in item sets. By way of example and without limitation, this can include the database system receiving the user's selection of the item set “computer sales San Francisco” from the drop-down list. A selection of an item set can be made by a user positioning an indicator, a pointer, or a cursor at a location where the item set is displayed on a user interface, or by the user's audio command via a microphone. For example, the user positions a touch pad cursor over the item “Francisco” in the item set “computer sales San Francisco,” and presses the enter key, which selects the item set “computer sales San Francisco.” In another example, the database system receives the user's selection of the item set “San Francisco computer sales James Jordan” from the drop-down list. In yet another example, the database system receives the user's selection of the item set “computer sales California” from the drop-down list.

After receiving a selection of an item set, the system executes a search based on the selected item set, box 124. In embodiments, this can include the database system executing a search using the suggested query items in the selected item set, “computer sales San Francisco.” In this example, the database system initially suggests the query items “computer sales California,” receives the user's selection of the items “computer sales” from the initially suggested query items, suggests additional query items based on the user-selected items “computer sales,” receives the user's selection of a suggested additional query item, and only then executes a search based on the user-selected additional query item. In contrast, conventional systems would immediately execute a search based on a user selecting anything from the initially suggested query items “computer sales California,” thereby preventing the user from submitting additional query terms until after the search that used the initially suggested query terms.

In another example, the database system executes a search using the suggested query items in the selected item set, “San Francisco computer sales James Jordan.” In a further example, the database system executes a search using the suggested query items in the selected item set, “computer sales California.” A search can be the database system discovering information for retrieval and presentation in response to a user query, based on the user's query items. The database system may store preprocessed search results for some frequent queries, such that the database system can more quickly transmit the search results to any user selecting the corresponding suggested query items. For example, the database system caches the search results for a search in response to the suggested query items “computer sales California” because the item set count for the item set “computer sales California” indicates that “computer sales California” is one of the most frequent item sets that is the basis for a search.

The method 100 may be repeated as desired. Although this disclosure describes the blocks 102-124 executing in a particular order, the blocks 102-124 may be executed in a different order. In other implementations, each of the blocks 102-124 may also be executed in combination with other blocks and/or some blocks may be divided into a different set of blocks.

FIG. 2 depicts an operational flow diagram illustrating a high level overview of a method 200 for suggesting query items based on frequent item sets. The method 200 may be implemented on either a centralized computing platform or in parallel on a distributed computing platform, such as on Map/Reduce or Spark. As a brief overview, a database system has a set of items with counts, such as Contact A with a count of 6, Contact B with a count of 5, Contact C with a Count of 4, and Contact D with a count of 5. The database system has both the tuple (A,C,B) and the tuple (C,A,D), and needs to sort these tuples to run through the tuples and export tuples and counts. To do that, the database system labels each item, and that labeling has two requirements. The labeling respects the counts of each item, i.e., if count(A)>count(B), then label(A)>label(B). The labeling is total, so for any items J and K, either label(J)>label(K) or label(K)>label(J), even if count(J)=count(K). The second requirement means that the labeling must be a total order. The reason it must be total order is that when the database system is done sorting, all the (A,B,C) tuples must be together and all the (A,D,C) tuples must be together, even if count(D)=count(B). The database system can reverse the ordering between labels, as long as the database system does it everywhere. If the database system doesn't make it a total order (i.e., just uses counts) then the database system can't separate B's and D's.

A system determines a count of each item in multiple item sets, block 202. A count quantifies the total occurrences, or support level, for each corresponding item in the sets. For example and without limitation, this can include the database system determining the count of 6 for Contact A, the count of 5 for Contact B, and the count of 4 for Contact C from the item sets (Contact A, Contact B), (Contact C, Contact A), (Contact C, Contact B, Contact A), (Contact B, Contact C), (Contact B, Contact A), (Contact A, Contact B, Contact C), and (Contact A). Although this example describes the database system counting each item in each of the item sets, the database system may count each item in a limited amount of the item sets. For example, the database system can only count the contacts in item sets that were recorded in the most recent 5 years so that the database system does not make recommendations based on contacts that were recorded more than 5 years ago.

Aspects of the database system are described below in reference to FIG. 4 and FIG. 5. A count can be a measure or a number of an item, such as 6 occurrences of Contact A in a collection of item sets, or the 7 times that a system user submitted a specific type of query that included the word “James.” An item can be anything that the database system can associate with a system user's set, such as a contact, a search term, an account, a lead, an opportunity, a product, a service, or any digital object. A set of items can be any group or collection of entities that are associated with a specific user at a period in time. Examples of item sets include the 9 contacts that an organization member purchased on Monday, the 10 contacts that the organization member purchased on Tuesday, the 8 contacts that the organization member searched for on Tuesday, the 13 accounts that an organization purchased on Wednesday morning, the 12 accounts that the organization purchased on Wednesday afternoon, and the 11 accounts that the organization searched for on Wednesday night.

After determining the count of each item, the system sorts each count into an ascending order, block 204. Sorting the counts of items enables the database system to identify items based on the frequency of the items' occurrences. By way of example and without limitation, this can include the database system sorting the count of 6, the count of 5, and the count of 4 into the ascending order of the count of 4, the count of 5, and the count of 6. Although this example describes the database system sorting counts in an ascending order, the database system can sort counts in a descending order. For example, the database system can sort the count of 4, the count of 5, and the count of 6 into the descending order of the count of 6, the count of 5, and the count of 4. Although not every item may have a unique count, the database system sorts the counts of items into a canonical ordering that provides a unique sorting order. Sorting can be to arrange systematically in a prescribed sequence, such as sorting a smaller number before a larger number. An ascending order can be an increasing sequence, such as the numbers 1, 2, and 3.

Having uniquely sorted the counts, the system assigns an identifier, from identifiers in an ascending order, to each item corresponding to each sorted count, block 206. The unique sorting order enables the database system to assign different identifiers to different items that have the same count, and assigning identifiers to items enables the database system to uniformly sort the items by sorting the identifiers. In embodiments, this can include the database system assigning identifier 1 to each Contact C, which corresponds to the count of 4, identifier 2 to each Contact B, which corresponds to the count of 5, and identifier 3 to each Contact A, which corresponds to the count of 6. Although this example describes the database system assigning increasing identifiers to the sorted counts, the database system can assign decreasing identifiers to the sorted accounts. For example, the database system assigns identifier 3 to each Contact C, which corresponds to the count of 4, identifier 2 to each Contact B, which corresponds to the count of 5, and identifier 1 to each Contact A, which corresponds to the count of 6. Assigning can be allocating or designating an identifier as a reference to a count, such as assigning the identifier 1 to each Contact C, which corresponds to the count of 4. An identifier can be a whole number used to reference a count, such as identifier 1 is the numeral 1 that is assigned to refer to the count of 4, as the identifiers need to be sortable.

Assigning can be allocating or designating an identifier as a reference to an item. For example, the database system temporarily replaces items in the item set (Contact A, Contact B, Contact C) with the identifiers 1, 2, and 3 to result in the set (identifier 3, identifier 2, identifier 1). In another example, the database system creates a temporary set (identifier 3, identifier 2, identifier 1) that is assigned to the item set (Contact A, Contact B, Contact C). In yet another example, the database system modifies the item set (Contact A, Contact B, Contact C) into the item set (Contact A, identifier 3; Contact B, identifier 2; Contact C, identifier 1).

Having assigned identifiers to set's items, the system optionally determines a count of each original sequence of items in multiple item sets, block 208. The count of each original sequence enables the database system to track the original listed order of the items in each item set. By way of example and without limitation, this can include the database system determining a count of 1 for the item set (Contact C, Contact B, Contact A) and determining a separate count of 1 for the item set (Contact A, Contact B, Contact C), and assigning a unique sequence identifier to each of these item sets. For each original sequence of items, the database system records the unique sequence identifier, the count of the original sequence of items, and the set of identifiers for the original sequence of items, with the set of identifiers sorted in descending order, as described below. The database system may record this information for an original sequence of items only if the count for the original sequence of items exceeds a threshold. An original sequence of items can be all of the items in an item set, listed in the order in which all of the items initially appeared in the item set. For example, the item set (Contact C, Contact B, Contact A) and the item set (Contact A, Contact B, Contact C) both contain only the same 3 items. However, since the items are listed in a different order in these two item sets, the database system counts each of these item sets separately as two different original sequences of items.

While the order in which contacts are listed may not appear to be significant, the order of other items in an item set may be significant enough to justify tracking the order of items in the item sets. For example, a user searches for potential contacts by submitting the search queries “San Francisco computer sales James Jordan” and “San Francisco computer sales Jordan James.” If the database system does not retain the order of the search terms, the database system may interpret these two sets of search terms as the same two searches for the same person who sells computers in San Francisco and who has the names of James and Jordan. If the database system retains the order of the search terms, the database system may interpret these two sets of search terms as searches for two different people who sell computers in San Francisco, one who has the given name of James and the family name of Jordan, and the other who has the given name of Jordan and the family name of James. In some embodiments, the database system retains an original sequence of an item set only if the count of the original sequence of the item set exceeds a threshold count, such that the original sequence of infrequently occurring item sets is not retained.

After assigning identifiers to set's items, and possibly tracking the original sequence of the items, the system sorts each identifier in each item set in descending order, block 210. Sorting identifiers in each set enables the database system to directly compare sets. In embodiments, this can include the database system sorting each identifier in each set in descending order, such as sorting the set (identifier 1, identifier 2, identifier 3) into the set (identifier 3, identifier 2, identifier 1) in descending order. Although this example describes the database system sorting each item set's identifiers in descending order, the database system can sort each item set's identifiers in ascending order. For example, the database system can sort the set (identifier 3, identifier 2, identifier 1) into the set (identifier 1, identifier 2, identifier 3) in ascending order. Descending order can be a decreasing sequence, such as the numbers 3, 2, and 1.

Having sorted each item sets' identifiers in descending order, the system optionally associates each original sequence of items with a corresponding item set that has each identifier sorted in descending order, block 212. The database system maps an item set to its original sequence of items, which will eventually enable the database system to make a recommendation using the original order of the items in an item set when the database system makes a recommendation based on the item set. For example and without limitation, this can include the database system mapping the item set (identifier 3, identifier 2, identifier 1), which corresponds to the sorted descending order of the items in the item set, to the item set (identifier 1, identifier 2, identifier 3), which corresponds to the original order of the items in the item set. Associating can be connecting or linking an item set with its original sequence of items, such as connecting the item set (identifier 3, identifier 2, identifier 1) with the original order item set (identifier 1, identifier 2, identifier 3).

After sorting each item sets' identifiers in descending order, the system partitions the item sets into a first group of item sets and a second group of item sets, with each item set in the first group of item sets including a common largest identifier, block 214. Partitioning the item sets into groups enables the database system to efficiently determine counts of item sets and subsets from a group of similar item sets. By way of example and without limitation, this can include the database system partitioning the identifiers sets into a first group that includes identifier 3 as the common largest identifier: (identifier 3, identifier 2, identifier 1), (identifier 3, identifier 2, identifier 1), (identifier 3, identifier 2), (identifier 3, identifier 2), (identifier 3, identifier 1), and (identifier 3) and a second group that has identifier 2 as the common largest identifier: (identifier 2, identifier 1). Although this example describes the database system partitioning item sets into groups of item sets based on a common largest identifier, the database system may partition item sets into groups of item sets based on a common smallest identifier. Upon partitioning the item sets into the first group of item sets, the database system may sort items in the first group of item sets.

A description of sorting items in a group of item sets is described below in reference to FIGS. 3A-B. Partitioning item sets into groups of item sets can be dividing, distributing, or separating item sets into mutually exclusive parts or portions, such as putting all item sets that have the identifier 3 as their common largest identifier into one collection of item sets, and putting all item sets that have the identifier 2 as their common largest identifier into another collection of item sets. In another example, all item sets that have the identifier 3 as their common smallest identifier are put into one collection of item sets, and all item sets that have the identifier 2 as their common smallest identifier are put into another collection of item sets. A group of item sets can be a collection or aggregation of item sets, such as the first group of item sets that have the identifier 3 as their largest identifier. A common largest identifier included in a group of items sets can be an identifier that has the largest value in each of the group's item sets, such as identifier 3 is the numerically biggest identifier in the first group of item sets.

Having partitioned the item sets into groups of item sets, the system determines a count for each subset of each item set of the first group of item sets, block 216. Determining the counts of subsets of item sets for one group of item sets enables the database system to aggregate all such counts for all such subsets for all such groups. In embodiments, this can include the database system determining the count of 2 for the subset (identifier 3, identifier 2, identifier 1), determining the count of 4 for the subset (identifier 3, identifier 2), determining the count of 3 for the subset (identifier 3, identifier 1), determining the count of 6 for the subset (identifier 3), determining the count of 2 for the subset (identifier 2, identifier 1), determining the count of 4 for the subset (identifier 2), and determining the count of 3 for the subset (identifier 1). Similarly, the database system determines the count of 1 for the subset (identifier 2, identifier 1), the count of 1 for the subset (identifier 2), and the count of 1 for the subset (identifier 1). A subset of items can be any or every part or portion of a collection or set of items, such as the subset (identifier 1) is a subset of the set (identifier 3, identifier 2, identifier 1), and the subset (identifier 3, identifier 2, identifier 1) is a subset of the set (identifier 3, identifier 2, identifier 1). Consequently, the database system can aggregate 3 counts of the subset (identifier 3, identifier 1) from 1 count of the subset (identifier 3, identifier 1) and 2 counts of the subset (identifier 3, identifier 2, identifier 1). A method of determining a count for each subset of each item set in a group of item sets is described below in reference to FIG. 3B.

After determining the count for each subset of each item set of the first group of item sets, the system determines the count of each subset of each item set by summing each count for each subset of each item set of the first group of item sets with each corresponding count for each corresponding subset of each item set of the second group of item sets, block 218. Determining the counts of each subset of each item set enables the database system to make recommendations based on these counts. For example and without limitation, this can include the database system summing the counts of the subsets for the groups, resulting in the count of 2 for the subset (identifier 3, identifier 2, identifier 1), the count of 4 for the subset (identifier 3, identifier 2), the count of 3 for the subset (identifier 3, identifier 1), the count of 6 for the subset (identifier 3), the count of 3 for the subset (identifier 2, identifier 1), the count of 5 for the subset (identifier 2), and the count of 4 for the subset (identifier 1). Summing counts can be adding or aggregating the counts to produce a combined result, such as adding the count of 2 for the subset (identifier 2, identifier 1) from the first group to the count of 1 for the subset (identifier 2, identifier 1) from the second group to result in the count of 3 for the subset (identifier 2, identifier 1) from both groups. The database system identifies frequent item sets faster than the Apriori algorithm identifies frequent item sets because the database system starts with item sets and then identifies subsets of the item sets, whereas the Apriori algorithm starts with individual items and then gradually extends these individual items to larger and larger item sets.

The database system may retain only item sets and/or items with sufficient support, which are item sets and/or items that occur more than a corresponding minimum threshold amount. Once the database system determines the support for each individual item, the database system may delete items that have insufficient support from their corresponding item sets. Additionally or alternatively, once the database system determines the support for each item set, the database system may delete item sets that have insufficient support.

Having determined the count of each subset of each item set, the system outputs a recommended item set based on the count of each subset of each item set, block 220. By way of example and without limitation, this can include the database system outputting a recommended item set (Contact B) to a system user who already purchased Contact A, because 4 of the 6 (66.6%) item sets that included Contact A also included Contact B, thereby exceeding the recommendation threshold of 60%. While some embodiments may also include (Contact C) in the recommended item set, other embodiments do not include (Contact C) in the recommended item set because only 3 of the 6 (50.0%) item sets that included Contact A also included Contact C, thereby failing to meet the recommendation threshold of 60%. In another example, the database system responds to a user's initial search terms set (San Francisco computer sales) by outputting a recommended item set (James Jordan) because most of the previous search term sets that included the search terms (San Francisco computer sales) also included the search terms (James Jordan). However, the database system does not list the recommended set as (Jordan James) because most of the search term sets that include the search terms (San Francisco computer sales James Jordan) list a search term order in which “James” is listed before “Jordan.”

The method 200 may be repeated as desired. Although this disclosure describes the blocks 202-220 executing in a particular order, the blocks 202-220 may be executed in a different order. In other implementations, each of the blocks 202-220 may also be executed in combination with other blocks and/or some blocks may be divided into a different set of blocks. Each of the blocks 202-220 may be implemented on either a centralized computing platform or in parallel on a distributed computing platform.

As an overview example of the process depicted in FIGS. 3A-B, a database system has a long item set 9876543 followed by a short item set 982. In this example, there are counts associated with items 6, 5, and 4, which need to get rolled up into the item 8. FIGS. 3A-B illustrate block diagrams 300 of extremely simplified examples of item sets and an array for identifying frequent item sets, in an embodiment. FIG. 3A includes identifier set 302 (identifier 3, identifier 2), identifier set 304 (identifier 3, identifier 1), identifier set 306 (identifier 3, identifier 2, identifier 1), identifier set 308 (identifier 2, identifier 1), identifier set 310 (identifier 3, identifier 2), identifier set 312 (identifier 3, identifier 2, identifier 1), and identifier set 314 (identifier 3), which are sorted in descending order. The identifier sets 302-314 correspond to the item sets (Contact A, Contact B), (Contact C, Contact A), (Contact C, Contact B, Contact A), (Contact B, Contact C), (Contact B, Contact A), (Contact A, Contact B, Contact C), and (Contact A), respectively.

The system partitions the item sets into the first group of item sets and the second group of item sets, with each group of item sets including a common largest identifier. For example, the database system partitions the item sets 302-306 and 310-314 into a first group of item sets that each have identifier 3 as the common largest identifier, and partitions the set 308 into a second group of item sets that has identifier 2 as the common largest identifier.

Then the system sorts each item set in the first group of item sets based on the identifiers in the item set position adjacent to the item set position for the common largest identifier. For example, since the first position in the item sets 302-306 and 310-314 includes the common largest identifier 3, the database system sorts these sets based on the identifiers included in the second position of these sets, which in these sets includes identifier 2, identifier 1, and null. An item set position can be a place or a location in an item set, such as the first position in the item set storing the common largest identifier. A position in an item set that is adjacent to another position in the item set can be a place or a location in an item set that is next to or adjoining another place or another position in the item set.

An item set can be considered as an array of positions from 0 to N. Given two item sets A and B, A<B (comes after B in the sort) if, in the first array position in which A and B differ, say 4, A[4]<B[4]. So if A is the item set [9,8,7,6,4,3] and B is the item set [9,8,7,6,5,2], A<B because 4<5. Next, the system sorts each item set that include the same identifier in the item set position adjacent to the item set position for the largest identifier based on the identifiers in the item set position adjacent to the item set position that is adjacent to the item set position for the common largest identifier. For example, since the item sets 302, 306, 310, and 312 have identifier 2 in the second position, the database system sorts these sets based on the identifiers in the third position, which in these sets includes identifier 1 and null. Although the sorting of the item sets 302-306 and 310-314 is complete in this extremely simplified example, the database system sorts item sets with more items by continuing to sort based on the next item set position until all of the item set positions have been sorted. The database system sorting the item sets 302-306 and 310-314 results in item sets that are prepared for sequential item set-by-item set comparison, as depicted in FIG. 3B.

The arrays 316-328 depicted in FIG. 3B are actually the same array used by the database system to determine the count for each subset of each item set of the first group of item sets, with the different reference numerals indicating the different states of this array at different points in time. The database system initializes the array 316 to (0, 0, 0), with the number of positions in the array 316 equaling the number of positions in the item set that has the largest number of items. The database system processes the item set 306 by modifying the array 316 (0, 0, 0) to become the array 318 (0, 0, 1). The count of 1 in the third position of the array 318 indicates that the items from the first position of the set 306 to the third position of the set 306 have been collectively identified 1 time so far by the database system.

The system determines whether an item set in a group of item sets matches the next item set in the group of item sets. For example, the database system determines whether the item set 306 (identifier 3, identifier 2, identifier 1) is the same as the item set 312 (identifier 3, identifier 2, identifier 1). One item set matching another item set can be the item sets being the same, equal, or identical, such as the item set 306 (identifier 3, identifier 2, identifier 1) being the same as the item set 312 (identifier 3, identifier 2, identifier 1).

If an item set in a group of item sets matches the next item set in the group of item sets, the system increments a count in a position in the array corresponding to a highest positioned item in the next item set. For example, since the item set 306 (identifier 3, identifier 2, identifier 1) is the same as the item set 312 (identifier 3, identifier 2, identifier 1), the database system modifies the array 318 (0, 0, 1) to become the array 320 (0, 0, 2). A highest positioned item in an item set can be an item that has a location that is associated with the largest numbered location in the item set, such as the third position in an item set that includes only three positions. The count of 2 in the third position of the array 320 indicates that the items from the first position of the set 312 to the third position of the set 312 have been collectively identified 2 times so far by the database system. Due to the sorting of item sets in the group of item sets, all of the item sets which are exactly the same will be sorted to be together, which enables the database system to quickly and efficiently sum the counts of the identical item sets.

Once again, the system determines whether one item set in the first group of item sets matches the next item set in the first group of item sets. For example, the database system determines whether the item set 312 (identifier 3, identifier 2, identifier 1) is the same as the item set 302 (identifier 3, identifier 2). If an item set in a group of item sets does not match the next item set in the group of item sets, the database system processes differing item sets. For example, since the item set 302 lacks identifier 1 that is present in the item set 312, the item set 312 does not match the item set 302, and the database system begins the process for the item sets determined to be not matching.

In the first process for item sets that the system determines to be not matching, the system identifies each subset of an item set that includes an item in the item set that lacks a match to a corresponding item in the next item set, a count for each subset of the item set being based on a count in a position in the array that corresponds to the item. For example, the database system identifies each subset of the item set 312 (identifier 3, identifier 2, identifier 1) that includes identifier 1 because identifier 1 lacks a match to any identifier in the item set 302 (identifier 3, identifier 2).

The database system determines the count of the subsets of item sets that include identifier 1 because the absence of identifier 1 in the set 302 indicates that subsequent sets may not include identifier 1. However, the database system minimizes the determination of counts for subsets of item sets by only counting subsets of item sets that include any identifier(s) that lacks a match in the next item set, which is identifier 1 in this example. The count for the subsets of the item set 312 that include identifier 1 is 2 because the array 320 has the count 2 in its third position, which corresponds to the third position in the item set 312 that has identifier 1. Therefore, the database system determines the count of 2 for the subset (identifier 3, identifier 2, identifier 1), the count of 2 for the subset (identifier 3, identifier 1), the count of 2 for the subset (identifier 2, identifier 1), and the count of 2 for the subset (identifier 1).

The database system may identify subsets of an item set based on the following algorithm. Given n positions of items in an item set, the item in each position can either appear in a subset of the item set or not appear in a subset of the item set. Therefore, the database system can identify subsets based on another array of Booleans, with the value of 1 indicating that an item in that position appears in a subset of the item set, and the value of 0 indicating that an item in that position does not appear in a subset of the item set. Consequently, the database system identifies 2^(n)−1 subsets, without identifying the empty subset. This Boolean array also corresponds to a number that is based on the maximum value represented by the array, and each position in the array also corresponds to another number. For example, if the item set 312 (identifier 3, identifier 2, identifier 1) is reversed to become the reversed item set (identifier 1, identifier 2, identifier 3), then the Boolean array for the reversed item set has a maximum value of 7 (1, 1, 1 in binary) and identifier 1 has a value of 1 (1, 0, 0 in binary). Therefore, the database system identifies all subsets of item set 312 that include identifier 1 by identifying the subset corresponding to the array's binary value of 7, decrementing the array's binary value of 7 to the binary value of 6, identifying the subset corresponding to the array's binary value of 6, and continuing decrementing the array's binary values and identifying the subsets corresponding to these values, including the identification of the subset corresponding to the array's binary value of 1.

More generally, given a previous item set of length m and a new item set, the database system calculates the length n of the common prefix. The database system executes the following algorithm.

For k = m to n + 1 descending do for i = 2^(k) −1 to 2^((k−1)) do for the previous item set do create an empty item set for j = 1 to k do if the jth bit of i is 1, add the item in the jth position (if tracking ordering, append the ordering ids and counts) od emit the item set with the count in position k (for ordering, also emit the ids and counts for the original orders) od od increment the count in position k−1 by the count in position k set the value in position k to 0 (if tracking ordering, free the list as well) od

Therefore, the database system only identifies subsets for the positions in an item set which changed from the previous item set to the next item set. If the database system identifies some subsets more than once, the database system sums the counts of the corresponding subsets after processing the final item set in the group of item sets.

In the second process for item sets that the system identifies as not matching, the system adds a count from a position in the array, corresponding to a highest positioned item in the first item set, to a position in the array that corresponds to a highest positioned item that matches between the first item set and the second item set. For example, the database system adds the count of 2 in the third position of the array 320, which corresponds to the highest positioned identifier 1 in the set 212, to the second position in the array 320 which corresponds to identifier 2 in the set 302, which is the highest positioned item that matches between the set 312 and the set 302. Adding a count from the third position in the array 320 to the second position in the array 322 results in re-initializing the third position in the array 322 to zero. At this point, the array 322 depicted in FIG. 3 would have the count of 2 in the second position and a count of 0 in the third position if the set 302 had an item in the third position. However, since the set 302 has no item in the third position, the database system nulls the third position in the array 322, and continues processing the array 322.

In the third process for item sets that the system identifies as not matching, the system adds a count in a position in the array that corresponds to a highest positioned item in the second item set. For example, the database system adds a count of 1 to the second position in the array 322, which corresponds to identifier 2 in the set 302, which is the highest positioned item in the set 302. Since the database system had just added a count of 2 to the second position in the array 322, the subsequent addition of the count of 1 to the second position in the array 322 results in the count of 3 in the second position of the array 222, as depicted in FIG. 3. The count of 3 in the second position of the array 322 indicates that the items from the first position of the set 302 to the second position of the set 302 have been collectively identified 3 times so far by the database system.

Continuing the example, the database system determines whether the item set 302 (identifier 3, identifier 2) is the same as the item set 310 (identifier 3, identifier 2). Since the item set 302 (identifier 3, identifier 2) is the same as the item set 310 (identifier 3, identifier 2), the database system modifies the array 322 (0, 3) to become the array 324 (0, 4). The count of 4 in the second position of the array 324 indicates that the items from the first position of the set 310 to the second position of the set 310 have been collectively identified 4 times so far by the database system.

Further to the example, the database system determines whether the item set 310 (identifier 3, identifier 2) is the same as the item set 304 (identifier 3, identifier 1). Since the item set 304 lacks identifier 2 that is present in the item set 310, the item set 310 does not match the item set 304. Therefore, the database system identifies each subset of the item set 310 (identifier 3, identifier 2) that includes identifier 2 because identifier 2 lacks a match to any identifier in the item set 304 (identifier 3, identifier 1). The database system determines the count of the subsets of item sets that include identifier 2 because the absence of identifier 2 in the set 304 indicates that subsequent sets may not include identifier 2. However, the database system minimizes the determination of counts for subsets of item sets by only counting subsets of item sets that include any identifier(s) that lacks a match in the next item set, which is identifier 2 in this example. The count for the subsets of the item set 310 that include identifier 2 is 4 because the array 324 has the count 4 in its second position, which corresponds to the second position in the item set 310 that has identifier 2. Therefore, the database system determines the count of 4 for the subset (identifier 3, identifier 2), and the count of 4 for the subset (identifier 2).

Then the database system adds the count of 4 in the second position of the array 324, which corresponds to the highest positioned identifier 2 in the set 210, to the first position in the array 326 which corresponds to identifier 3 in the set 304, which is the highest positioned item that matches between the set 310 and the set 304. Adding a count from the second position in the array 324 to the first position in the array 326 results in re-setting the second position in the array 326 to zero. At this point, the array 326 depicted in FIG. 3 would have the count of 4 in the first position and a count of 0 in the third position. However, the database system continues processing the array 326 by adding a count of 1 to the second position in the array 326, which corresponds to identifier 1 in the set 304, which is the highest positioned item in the set 304. The count of 1 in the second position of the array 326 indicates that the items from the first position of the set 304 to the second position of the set 304 have been collectively identified 1 time so far by the database system. The count of 4 in the first position of the array 326 indicates that the item in the first position of the set 304 has been collectively identified 4 additional times, or 5 total times, so far by the database system.

Next in the example, the database system determines whether the item set 304 (identifier 3, identifier 1) is the same as the item set 314 (identifier 3). Since the item set 314 lacks identifier 1 that is present in the item set 310, the item set 304 does not match the item set 314. Therefore, the database system identifies each subset of the item set 304 (identifier 3, identifier 1) that includes identifier 1 because identifier 1 lacks a match to any identifier in the item set 314 (identifier 3). The database system determines the count of the subsets of item sets that include identifier 1 because the absence of identifier 1 in the set 314 indicates that subsequent sets may not include identifier 1. However, the database system minimizes the determination of counts for subsets of item sets by only counting subsets of item sets that include any identifier(s) that lacks a match in the next item set, which is identifier 1 in this example. The count for the subsets of the item set 304 that include identifier 1 is 1 because the array 326 has the count 1 in its second position, which corresponds to the second position in the item set 304 that has identifier 1. Therefore, the database system determines the count of 1 for the subset (identifier 3, identifier 1), and the count of 1 for the subset (identifier 1). The database system previously determined the count of 2 for the subset (identifier 3, identifier 1), and the count of 2 for the subset (identifier 1) when the database system determined that the set 302 lacked identifier 1. After the database system subsequently identifies the final item set in the first group of item sets, the database system aggregates counts for corresponding subsets, thereby resulting in the count of 3 for the subset (identifier 3, identifier 1), and the count of 3 for the subset (identifier 1).

Then the database system adds the count of 1 in the second position of the array 324, which corresponds to the highest positioned identifier 1 in the set 304, to the first position in the array 328 which corresponds to identifier 3 in the set 314, which is the highest positioned item that matches between the set 304 and the set 314. Adding a count from the second position in the array 326 to the first position in the array 328 results in re-setting the second position in the array 328 to zero. At this point, the array 328 depicted in FIG. 3 would have the count of 5 in the first position and a count of 0 in the second position if the set 314 had an item in the second position. However, since the set 314 has no item in the second position, the database system nulls the second position in the array 328, and continues processing the array 328 by adding a count of 1 to the first position in the array 328, which corresponds to identifier 3 in the set 314, which is the highest positioned item in the set 314. Since the database system had just added a count of 1 to the count of 4 in the first position in the array 328, the subsequent addition of the count of 1 to the first position in the array 328 results in the count of 6 in the first position of the array 328, as depicted in FIG. 3. The count of 6 in the first position of the array 328 indicates that the item in the first position of the set 314 has been collectively identified 6 times so far by the database system.

Upon identifying an item set as the final item set in the first group of item sets, the database system identifies each subset of the final item set, with the count for a subset of the final item set being based on the count in a position in the array that corresponds to the highest positioned item that is common to the subset. For example, the database system determines the count of 6 for the subset (identifier 3) because of the count of 6 in the first position of the array 328, corresponding to identifier 3 which is the highest positioned item that is common to the subset (identifier 3). Although this extremely simplified example results in the database system identifying only a single subset based on the final item set including only a single item, the database system may identify multiple subsets based on a final item set that includes multiple items. Examples of the database system identifying multiple subsets based on an item set that includes multiple items are described above.

In another example, if the set 304 was the final item set in the first group of item sets, then the database system would have identified each subset of the item set 304 (identifier 3, identifier 1). The count for the subsets of the item set 304 that include identifier 1 is 1 because the array 326 has the count 1 in its second position, which corresponds to the second position in the item set 304 that has identifier 1. Therefore, the database system would determine the count of 1 for the subset (identifier 3, identifier 1), and the count of 1 for the subset (identifier 1). The count for the subsets of the item set 304 that include identifier 3 is 4 because the array 326 has the count 4 in its first position, which corresponds to the first position in the item set 304 that has identifier 3. Therefore, the database system would determine the count of 4 for the subset (identifier 3).

If the database system is tracking the original sequences of items, the database system maintains an array or list of the original sequences of items. When the database system identifies that the previous item set in a group of item sets does not match the next item set in the group of item sets, the database system associates the counts and subsets for these item sets with the list of the original sequences of items. Just as the database system determines the count of each subset of each item set, the database system also determines the count of each original sequence of items that corresponds to each of these subsets. When the database system determines the count of each subset of each item set in each group of item sets, the database system can union the counts of subsets associated with the list of original sequences of items that are associated with each group of item sets, thereby enabling the database system to determine the count for each original sequence of items.

If the entire algorithm is executing on multiple computing platforms at once, many platforms are generating the same item sets that need to be combined. For example, if a first group of item sets has the highest item number 9 and includes the item set 9765, while a second group of item sets has highest the highest item number 8 and includes the item set 8765, the algorithm processing both groups will generate the item subset 765, each with some count and potentially a set of orderings. From the map/reduce perspective this has been the map part. In the reduce part, the algorithm sums the counts by concatenating the lists of original sequences because the lists from the first group are all from original item sets that contain item number 9 and the lists from the second group are all from original item sets that do not include item number 9, but do include item number 8. In terms of item sets, the algorithm is done. But in terms of ordering, the algorithm needs to run through the lists of original sequences and determine the probabilities of the orderings, so that, for example, when suggesting a next word, the algorithm knows what display order to suggest.

If the entire algorithm is executing on multiple computing platforms at once, many platforms are generating the same item sets that need to be combined. For example, if a first group of item sets has the highest item number 9 and includes the item set 9765, while a second group of item sets has highest the highest item number 8 and includes the item set 8765, the algorithm processing both groups will generate the item subset 765, each with some count and potentially a set of orderings. From the map/reduce perspective this has been the map part. In the reduce part, the algorithm sums the counts by concatenating the lists of original sequences because the lists from the first group are all from original item sets that contain item number 9 and the lists from the second group are all from original item sets that do not include item number 9, but do include item number 8. In terms of item sets, the algorithm is done. But in terms of ordering, the algorithm needs to run through the lists of original sequences and determine the probabilities of the orderings, so that, for example, when suggesting a next word, the algorithm knows what display order to suggest.

System Overview

FIG. 4 illustrates a block diagram of an environment 410 wherein an on-demand database service might be used. The environment 410 may include user systems 412, a network 414, a system 416, a processor system 417, an application platform 418, a network interface 420, a tenant data storage 422, a system data storage 424, program code 426, and a process space 428. In other embodiments, the environment 410 may not have all of the components listed and/or may have other elements instead of, or in addition to, those listed above.

The environment 410 is an environment in which an on-demand database service exists. A user system 412 may be any machine or system that is used by a user to access a database user system. For example, any of the user systems 412 may be a handheld computing device, a mobile phone, a laptop computer, a work station, and/or a network of computing devices. As illustrated in FIG. 4 (and in more detail in FIG. 5) the user systems 412 might interact via the network 414 with an on-demand database service, which is the system 416.

An on-demand database service, such as the system 416, is a database system that is made available to outside users that do not need to necessarily be concerned with building and/or maintaining the database system, but instead may be available for their use when the users need the database system (e.g., on the demand of the users). Some on-demand database services may store information from one or more tenants stored into tables of a common database image to form a multi-tenant database system (MTS). Accordingly, the “on-demand database service 416” and the “system 416” will be used interchangeably herein. A database image may include one or more database objects. A relational database management system (RDMS) or the equivalent may execute storage and retrieval of information against the database object(s). The application platform 418 may be a framework that allows the applications of the system 416 to run, such as the hardware and/or software, e.g., the operating system. In an embodiment, the on-demand database service 416 may include the application platform 418 which enables creation, managing and executing one or more applications developed by the provider of the on-demand database service, users accessing the on-demand database service via user systems 412, or third party application developers accessing the on-demand database service via the user systems 412.

The users of the user systems 412 may differ in their respective capacities, and the capacity of a particular user system 412 might be entirely determined by permissions (permission levels) for the current user. For example, where a salesperson is using a particular user system 412 to interact with the system 416, that user system 412 has the capacities allotted to that salesperson. However, while an administrator is using that user system 412 to interact with the system 416, that user system 412 has the capacities allotted to that administrator. In systems with a hierarchical role model, users at one permission level may have access to applications, data, and database information accessible by a lower permission level user, but may not have access to certain applications, database information, and data accessible by a user at a higher permission level. Thus, different users will have different capabilities with regard to accessing and modifying application and database information, depending on a user's security or permission level.

The network 414 is any network or combination of networks of devices that communicate with one another. For example, the network 414 may be any one or any combination of a LAN (local area network), WAN (wide area network), telephone network, wireless network, point-to-point network, star network, token ring network, hub network, or other appropriate configuration. As the most common type of computer network in current use is a TCP/IP (Transfer Control Protocol and Internet Protocol) network, such as the global internetwork of networks often referred to as the “Internet” with a capital “I,” that network will be used in many of the examples herein. However, it should be understood that the networks that the one or more implementations might use are not so limited, although TCP/IP is a frequently implemented protocol.

The user systems 412 might communicate with the system 416 using TCP/IP and, at a higher network level, use other common Internet protocols to communicate, such as HTTP, FTP, AFS, WAP, etc. In an example where HTTP is used, the user systems 412 might include an HTTP client commonly referred to as a “browser” for sending and receiving HTTP messages to and from an HTTP server at the system 416. Such an HTTP server might be implemented as the sole network interface between the system 416 and the network 414, but other techniques might be used as well or instead. In some implementations, the interface between the system 416 and the network 414 includes load sharing functionality, such as round-robin HTTP request distributors to balance loads and distribute incoming HTTP requests evenly over a plurality of servers. At least as for the users that are accessing that server, each of the plurality of servers has access to the MTS' data; however, other alternative configurations may be used instead.

In one embodiment, the system 416, shown in FIG. 4, implements a web-based customer relationship management (CRM) system. For example, in one embodiment, the system 416 includes application servers configured to implement and execute CRM software applications as well as provide related data, code, forms, webpages and other information to and from the user systems 412 and to store to, and retrieve from, a database system related data, objects, and Webpage content. With a multi-tenant system, data for multiple tenants may be stored in the same physical database object, however, tenant data typically is arranged so that data of one tenant is kept logically separate from that of other tenants so that one tenant does not have access to another tenant's data, unless such data is expressly shared. In certain embodiments, the system 416 implements applications other than, or in addition to, a CRM application. For example, the system 416 may provide tenant access to multiple hosted (standard and custom) applications, including a CRM application. User (or third party developer) applications, which may or may not include CRM, may be supported by the application platform 418, which manages creation, storage of the applications into one or more database objects and executing of the applications in a virtual machine in the process space of the system 416.

One arrangement for elements of the system 416 is shown in FIG. 4, including the network interface 420, the application platform 418, the tenant data storage 422 for tenant data 423, the system data storage 424 for system data 425 accessible to the system 416 and possibly multiple tenants, the program code 426 for implementing various functions of the system 416, and the process space 428 for executing MTS system processes and tenant-specific processes, such as running applications as part of an application hosting service. Additional processes that may execute on the system 416 include database indexing processes.

Several elements in the system shown in FIG. 4 include conventional, well-known elements that are explained only briefly here. For example, each of the user systems 412 could include a desktop personal computer, workstation, laptop, PDA, cell phone, or any wireless access protocol (WAP) enabled device or any other computing device capable of interfacing directly or indirectly to the Internet or other network connection. Each of the user systems 412 typically runs an HTTP client, e.g., a browsing program, such as Microsoft's Internet Explorer browser, Netscape's Navigator browser, Opera's browser, or a WAP-enabled browser in the case of a cell phone, PDA or other wireless device, or the like, allowing a user (e.g., subscriber of the multi-tenant database system) of the user systems 412 to access, process and view information, pages and applications available to it from the system 416 over the network 414. Each of the user systems 412 also typically includes one or more user interface devices, such as a keyboard, a mouse, trackball, touch pad, touch screen, pen or the like, for interacting with a graphical user interface (GUI) provided by the browser on a display (e.g., a monitor screen, LCD display, etc.) in conjunction with pages, forms, applications and other information provided by the system 416 or other systems or servers. For example, the user interface device may be used to access data and applications hosted by the system 416, and to perform searches on stored data, and otherwise allow a user to interact with various GUI pages that may be presented to a user. As discussed above, embodiments are suitable for use with the Internet, which refers to a specific global internetwork of networks. However, it should be understood that other networks can be used instead of the Internet, such as an intranet, an extranet, a virtual private network (VPN), a non-TCP/IP based network, any LAN or WAN or the like.

According to one embodiment, each of the user systems 412 and all of its components are operator configurable using applications, such as a browser, including computer code run using a central processing unit such as an Intel Pentium® processor or the like. Similarly, the system 416 (and additional instances of an MTS, where more than one is present) and all of their components might be operator configurable using application(s) including computer code to run using a central processing unit such as the processor system 417, which may include an Intel Pentium® processor or the like, and/or multiple processor units. A computer program product embodiment includes a machine-readable storage medium (media) having instructions stored thereon/in which can be used to program a computer to perform any of the processes of the embodiments described herein. Computer code for operating and configuring the system 416 to intercommunicate and to process webpages, applications and other data and media content as described herein are preferably downloaded and stored on a hard disk, but the entire program code, or portions thereof, may also be stored in any other volatile or non-volatile memory medium or device as is well known, such as a ROM or RAM, or provided on any media capable of storing program code, such as any type of rotating media including floppy disks, optical discs, digital versatile disk (DVD), compact disk (CD), microdrive, and magneto-optical disks, and magnetic or optical cards, nanosystems (including molecular memory ICs), or any type of media or device suitable for storing instructions and/or data. Additionally, the entire program code, or portions thereof, may be transmitted and downloaded from a software source over a transmission medium, e.g., over the Internet, or from another server, as is well known, or transmitted over any other conventional network connection as is well known (e.g., extranet, VPN, LAN, etc.) using any communication medium and protocols (e.g., TCP/IP, HTTP, HTTPS, Ethernet, etc.) as are well known. It will also be appreciated that computer code for implementing embodiments can be implemented in any programming language that can be executed on a client system and/or server or server system such as, for example, C, C++, HTML, any other markup language, Java™, JavaScript, ActiveX, any other scripting language, such as VBScript, and many other programming languages as are well known may be used. (Java™ is a trademark of Sun Microsystems, Inc.).

According to one embodiment, the system 416 is configured to provide webpages, forms, applications, data and media content to the user (client) systems 412 to support the access by the user systems 412 as tenants of the system 416. As such, the system 416 provides security mechanisms to keep each tenant's data separate unless the data is shared. If more than one MTS is used, they may be located in close proximity to one another (e.g., in a server farm located in a single building or campus), or they may be distributed at locations remote from one another (e.g., one or more servers located in city A and one or more servers located in city B). As used herein, each MTS could include one or more logically and/or physically connected servers distributed locally or across one or more geographic locations. Additionally, the term “server” is meant to include a computer system, including processing hardware and process space(s), and an associated storage system and database application (e.g., OODBMS or RDBMS) as is well known in the art. It should also be understood that “server system” and “server” are often used interchangeably herein. Similarly, the database object described herein can be implemented as single databases, a distributed database, a collection of distributed databases, a database with redundant online or offline backups or other redundancies, etc., and might include a distributed database or storage network and associated processing intelligence.

FIG. 5 also illustrates the environment 410. However, in FIG. 5 elements of the system 416 and various interconnections in an embodiment are further illustrated. FIG. 5 shows that the each of the user systems 412 may include a processor system 412A, a memory system 412B, an input system 412C, and an output system 412D. FIG. 5 shows the network 414 and the system 416. FIG. 5 also shows that the system 416 may include the tenant data storage 422, the tenant data 423, the system data storage 424, the system data 425, a User Interface (UI) 530, an Application Program Interface (API) 532, a PL/SOQL 534, save routines 536, an application setup mechanism 538, applications servers 500 ₁-500 _(N), a system process space 502, tenant process spaces 504, a tenant management process space 510, a tenant storage area 512, a user storage 514, and application metadata 516. In other embodiments, the environment 410 may not have the same elements as those listed above and/or may have other elements instead of, or in addition to, those listed above.

The user systems 412, the network 414, the system 416, the tenant data storage 422, and the system data storage 424 were discussed above in reference to FIG. 4. Regarding the user systems 412, the processor system 412A may be any combination of one or more processors. The memory system 412B may be any combination of one or more memory devices, short term, and/or long term memory. The input system 412C may be any combination of input devices, such as one or more keyboards, mice, trackballs, scanners, cameras, and/or interfaces to networks. The output system 412D may be any combination of output devices, such as one or more monitors, printers, and/or interfaces to networks. As shown by FIG. 5, the system 416 may include the network interface 420 (of FIG. 4) implemented as a set of HTTP application servers 500, the application platform 418, the tenant data storage 422, and the system data storage 424. Also shown is the system process space 502, including individual tenant process spaces 504 and the tenant management process space 510. Each application server 500 may be configured to access tenant data storage 422 and the tenant data 423 therein, and the system data storage 424 and the system data 425 therein to serve requests of the user systems 412. The tenant data 423 might be divided into individual tenant storage areas 512, which can be either a physical arrangement and/or a logical arrangement of data. Within each tenant storage area 512, the user storage 514 and the application metadata 516 might be similarly allocated for each user. For example, a copy of a user's most recently used (MRU) items might be stored to the user storage 514. Similarly, a copy of MRU items for an entire organization that is a tenant might be stored to the tenant storage area 512. The UI 530 provides a user interface and the API 532 provides an application programmer interface to the system 416 resident processes to users and/or developers at the user systems 412. The tenant data and the system data may be stored in various databases, such as one or more Oracle™ databases.

The application platform 418 includes the application setup mechanism 538 that supports application developers' creation and management of applications, which may be saved as metadata into the tenant data storage 422 by the save routines 536 for execution by subscribers as one or more tenant process spaces 504 managed by the tenant management process 510 for example. Invocations to such applications may be coded using the PL/SOQL 534 that provides a programming language style interface extension to the API 532. A detailed description of some PL/SOQL language embodiments is discussed in commonly owned U.S. Pat. No. 7,730,478 entitled, METHOD AND SYSTEM FOR ALLOWING ACCESS TO DEVELOPED APPLICATIONS VIA A MULTI-TENANT ON-DEMAND DATABASE SERVICE, by Craig Weissman, filed Sep. 21, 2007, which is incorporated in its entirety herein for all purposes. Invocations to applications may be detected by one or more system processes, which manages retrieving the application metadata 516 for the subscriber making the invocation and executing the metadata as an application in a virtual machine.

Each application server 500 may be communicably coupled to database systems, e.g., having access to the system data 425 and the tenant data 423, via a different network connection. For example, one application server 500 ₁ might be coupled via the network 414 (e.g., the Internet), another application server 500 _(N-1) might be coupled via a direct network link, and another application server 500 _(N) might be coupled by yet a different network connection. Transfer Control Protocol and Internet Protocol (TCP/IP) are typical protocols for communicating between application servers 500 and the database system. However, it will be apparent to one skilled in the art that other transport protocols may be used to optimize the system depending on the network interconnect used.

In certain embodiments, each application server 500 is configured to handle requests for any user associated with any organization that is a tenant. Because it is desirable to be able to add and remove application servers from the server pool at any time for any reason, there is preferably no server affinity for a user and/or organization to a specific application server 500. In one embodiment, therefore, an interface system implementing a load balancing function (e.g., an F5 Big-IP load balancer) is communicably coupled between the application servers 500 and the user systems 412 to distribute requests to the application servers 500. In one embodiment, the load balancer uses a least connections algorithm to route user requests to the application servers 500. Other examples of load balancing algorithms, such as round robin and observed response time, also can be used. For example, in certain embodiments, three consecutive requests from the same user could hit three different application servers 500, and three requests from different users could hit the same application server 500. In this manner, the system 416 is multi-tenant, wherein the system 416 handles storage of, and access to, different objects, data and applications across disparate users and organizations.

As an example of storage, one tenant might be a company that employs a sales force where each salesperson uses the system 416 to manage their sales process. Thus, a user might maintain contact data, leads data, customer follow-up data, performance data, goals and progress data, etc., all applicable to that user's personal sales process (e.g., in the tenant data storage 422). In an example of a MTS arrangement, since all of the data and the applications to access, view, modify, report, transmit, calculate, etc., can be maintained and accessed by a user system having nothing more than network access, the user can manage his or her sales efforts and cycles from any of many different user systems. For example, if a salesperson is visiting a customer and the customer has Internet access in their lobby, the salesperson can obtain critical updates as to that customer while waiting for the customer to arrive in the lobby.

While each user's data might be separate from other users' data regardless of the employers of each user, some data might be organization-wide data shared or accessible by a plurality of users or all of the users for a given organization that is a tenant. Thus, there might be some data structures managed by the system 416 that are allocated at the tenant level while other data structures might be managed at the user level. Because an MTS might support multiple tenants including possible competitors, the MTS should have security protocols that keep data, applications, and application use separate. Also, because many tenants may opt for access to an MTS rather than maintain their own system, redundancy, up-time, and backup are additional functions that may be implemented in the MTS. In addition to user-specific data and tenant specific data, the system 416 might also maintain system level data usable by multiple tenants or other data. Such system level data might include industry reports, news, postings, and the like that are sharable among tenants.

In certain embodiments, the user systems 412 (which may be client systems) communicate with the application servers 500 to request and update system-level and tenant-level data from the system 416 that may require sending one or more queries to the tenant data storage 422 and/or the system data storage 424. The system 416 (e.g., an application server 500 in the system 416) automatically generates one or more SQL statements (e.g., one or more SQL queries) that are designed to access the desired information. The system data storage 424 may generate query plans to access the requested data from the database.

Each database can generally be viewed as a collection of objects, such as a set of logical tables, containing data fitted into predefined categories. A “table” is one representation of a data object, and may be used herein to simplify the conceptual description of objects and custom objects. It should be understood that “table” and “object” may be used interchangeably herein. Each table generally contains one or more data categories logically arranged as columns or fields in a viewable schema. Each row or record of a table contains an instance of data for each category defined by the fields. For example, a CRM database may include a table that describes a customer with fields for basic contact information such as name, address, phone number, fax number, etc. Another table might describe a purchase order, including fields for information such as customer, product, sale price, date, etc. In some multi-tenant database systems, standard entity tables might be provided for use by all tenants. For CRM database applications, such standard entities might include tables for Account, Contact, Lead, and Opportunity data, each containing pre-defined fields. It should be understood that the word “entity” may also be used interchangeably herein with “object” and “table”.

In some multi-tenant database systems, tenants may be allowed to create and store custom objects, or they may be allowed to customize standard entities or objects, for example by creating custom fields for standard objects, including custom index fields. U.S. Pat. No. 7,779,039, filed Apr. 2, 2004, entitled “Custom Entities and Fields in a Multi-Tenant Database System”, which is hereby incorporated herein by reference, teaches systems and methods for creating custom objects as well as customizing standard objects in a multi-tenant database system. In certain embodiments, for example, all custom entity data rows are stored in a single multi-tenant physical table, which may contain multiple logical tables per organization. It is transparent to customers that their multiple “tables” are in fact stored in one large table or that their data may be stored in the same table as the data of other customers.

While one or more implementations have been described by way of example and in terms of the specific embodiments, it is to be understood that one or more implementations are not limited to the disclosed embodiments. To the contrary, it is intended to cover various modifications and similar arrangements as would be apparent to those skilled in the art. Therefore, the scope of the appended claims should be accorded the broadest interpretation so as to encompass all such modifications and similar arrangements. 

1. A system for suggesting query items based on frequent item sets, the apparatus comprising: one or more processors; and a non-transitory computer readable medium storing a plurality of instructions, which when executed, cause the one or more processors to: identify, by a database system, a first item comprising a character sequence and a second item comprising the character sequence, in response to receiving the character sequence entered in a search box; identify, by the database system, a first item set comprising the first item and a second item set comprising the second item; output, by the database system, the first item set and the second item set to a location associated with the search box; identify, by the database system, a third item set comprising a third item and a fourth item set comprising the third item, in response to receiving a selection of the third item from the first item set; output, by the database system, the third item set and the fourth item set to the location associated with the search box; and execute, by the database system, a search based on any selected item set, in response to receiving a selection of any item set from the location associated with the search box.
 2. The system of claim 1, wherein identifying the first item and the second item is based on the first item and the second item being associated with corresponding item counts that are larger than corresponding item counts associated with a plurality of items.
 3. The system of claim 1, wherein identifying the first item set and the second item set is based on the first item set and the second item set being associated with corresponding item set counts that are larger than corresponding item set counts associated with a plurality of item sets.
 4. The system of claim 1, wherein the first item set one of includes and excludes an association with a prior search.
 5. The system of claim 1, wherein the second item set one of excludes and includes an association with a prior search.
 6. The system of claim 1, wherein outputting the first item set to the location associated with the search box comprises outputting items from the first item set in an item sequence associated with a prior search.
 7. The system of claim 1, comprising further instructions, which when executed, cause the one or more processors to: identify, by the database system, a fifth item set comprising a fourth item and a sixth item set comprising the fourth item, in response to receiving a selection of the fourth item from the third item set; and output, by the database system, the fifth item set and the sixth item set to the location associated with the search box.
 8. A computer program product comprising computer-readable program code to be executed by one or more processors when retrieved from a non-transitory computer-readable medium, the program code including instructions to: identify, by a database system, a first item comprising a character sequence and a second item comprising the character sequence, in response to receiving the character sequence entered in a search box; identify, by the database system, a first item set comprising the first item and a second item set comprising the second item; output, by the database system, the first item set and the second item set to a location associated with the search box; identify, by the database system, a third item set comprising a third item and a fourth item set comprising the third item, in response to receiving a selection of the third item from the first item set; output, by the database system, the third item set and the fourth item set to the location associated with the search box; and execute, by the database system, a search based on any selected item set, in response to receiving a selection of any item set from the location associated with the search box.
 9. The computer program product of claim 8, wherein identifying the first item and the second item is based on the first item and the second item being associated with corresponding item counts that are larger than corresponding item counts associated with a plurality of items.
 10. The computer program product of claim 8, wherein identifying the first item set and the second item set is based on the first item set and the second item set being associated with corresponding item set counts that are larger than corresponding item set counts associated with a plurality of item sets.
 11. The computer program product of claim 8, wherein the first item set one of includes and excludes an association with a prior search.
 12. The computer program product of claim 8, wherein the second item set one of excludes and includes an association with a prior search.
 13. The computer program product of claim 8, wherein outputting the first item set to the location associated with the search box comprises outputting items from the first item set in an item sequence associated with a prior search.
 14. The computer program product of claim 8, wherein the program code comprises further instructions to: identify, by the database system, a fifth item set comprising a fourth item and a sixth item set comprising the fourth item, in response to receiving a selection of the fourth item from the third item set; and output, by the database system, the fifth item set and the sixth item set to the location associated with the search box.
 15. A method for suggesting query items based on frequent item sets, the method comprising: identifying, by a database system, a first item comprising a character sequence and a second item comprising the character sequence, in response to receiving the character sequence entered in a search box; identifying, by the database system, a first item set comprising the first item and a second item set comprising the second item; outputting, by the database system, the first item set and the second item set to a location associated with the search box; identifying, by the database system, a third item set comprising a third item and a fourth item set comprising the third item, in response to receiving a selection of the third item from the first item set; outputting, by the database system, the third item set and the fourth item set to the location associated with the search box; and executing, by the database system, a search based on any selected item set, in response to receiving a selection of any item set from the location associated with the search box.
 16. The method of claim 15, wherein identifying the first item and the second item is based on the first item and the second item being associated with corresponding item counts that are larger than corresponding item counts associated with a plurality of items.
 17. The method of claim 15, wherein identifying the first item set and the second item set is based on the first item set and the second item set being associated with corresponding item set counts that are larger than corresponding item set counts associated with a plurality of item sets.
 18. The method of claim 15, wherein the first item set one of includes and excludes an association with a first prior search, and the second item set one of excludes and includes an association with a second prior search.
 19. The method of claim 15, wherein outputting the first item set to the location associated with the search box comprises outputting items from the first item set in an item sequence associated with a prior search.
 20. The method of claim 15, wherein the method further comprises: identifying, by the database system, a fifth item set comprising a fourth item and a sixth item set comprising the fourth item, in response to receiving a selection of the fourth item from the third item set; and outputting, by the database system, the fifth item set and the sixth item set to the location associated with the search box. 